"The Door to Another World" is a captivating story that blends romance and mystery with a twist of time travel. Ji-Ae, a confident and solitary teenager, stumbles upon a mysterious door at school that she's never seen before. To her astonishment, the lock matches the key her grandmother gave her on her 15th birthday-a key she's never understood until now. When she inserts the key, she is transported back in time, unlocking a hidden world full of secrets, and a romance that spans both the past and present.
As Ji-Ae navigates her newfound connection to the past, she finds herself falling for two boys: one in the present, Seung-Ho, the charming and enigmatic class president, and one in the past, whose presence ties into the mystery of the key and her family's history. Torn between two worlds, Ji-Ae must unravel the truth behind the key, her grandmother's gift, and the timeless love that connects them all.